From fd93c068ada2ff3bf57a794f4eabd24558ea83f4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Magalh=C3=A3es?= <joamag@gmail.com>
Date: Sun, 26 Jun 2022 01:12:38 +0100
Subject: [PATCH] feat: initial MMU support Added more instructions
---
examples/sdl/src/main.rs | 2 ++
src/cpu.rs | 61 ++++++++++++++++++++++++++++++++++++----
src/mmu.rs | 30 +++++++++++++++++++-
src/ppu.rs | 2 +-
4 files changed, 87 insertions(+), 8 deletions(-)
diff --git a/examples/sdl/src/main.rs b/examples/sdl/src/main.rs
index a8c90f31..51903a1c 100644
--- a/examples/sdl/src/main.rs
+++ b/examples/sdl/src/main.rs
@@ -7,4 +7,6 @@ fn main() {
game_boy.clock();
game_boy.clock();
game_boy.clock();
+ game_boy.clock();
+ game_boy.clock();
}
diff --git a/src/cpu.rs b/src/cpu.rs
index 20d5207e..7351f6be 100644
--- a/src/cpu.rs
+++ b/src/cpu.rs
@@ -1,6 +1,6 @@
use crate::mmu::Mmu;
-pub const INSTRUCTIONS: [(fn(&mut Cpu), u8, &'static str); 176] = [
+pub const INSTRUCTIONS: [(fn(&mut Cpu), u8, &'static str); 208] = [
// 0x0 opcodes
(nop, 4, "NOP"),
(ld_bc_u16, 12, "LD BC, NN"),
@@ -37,7 +37,7 @@ pub const INSTRUCTIONS: [(fn(&mut Cpu), u8, &'static str); 176] = [
(nop, 4, "NOP"),
// 0x2 opcodes
(nop, 4, "NOP"),
- (nop, 4, "NOP"),
+ (ld_hl_u16, 12, "LD HL, u16"),
(nop, 4, "NOP"),
(nop, 4, "NOP"),
(nop, 4, "NOP"),
@@ -55,7 +55,7 @@ pub const INSTRUCTIONS: [(fn(&mut Cpu), u8, &'static str); 176] = [
// 0x3 opcodes
(nop, 4, "NOP"),
(ld_sp_u16, 12, "LD SP, NN"),
- (nop, 4, "NOP"),
+ (ld_mhld_a, 8, "LD [HL]-, A"),
(nop, 4, "NOP"),
(nop, 4, "NOP"),
(nop, 4, "NOP"),
@@ -188,6 +188,40 @@ pub const INSTRUCTIONS: [(fn(&mut Cpu), u8, &'static str); 176] = [
(nop, 4, "NOP"),
(nop, 4, "NOP"),
(xor_a_a, 4, "XOR A, A"),
+ // 0xb opcodes
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ // 0xc opcodes
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
+ (nop, 4, "NOP"),
];
pub struct Cpu {
@@ -238,10 +272,10 @@ impl Cpu {
let instruction = INSTRUCTIONS[opcode as usize];
let (instruction_fn, instruction_size, instruction_str) = instruction;
+ println!("{} ({:#x})", instruction_str, opcode);
+
instruction_fn(self);
self.clocks = self.clocks.wrapping_add(instruction_size as u32);
-
- println!("{} ({:#x})", instruction_str, opcode)
}
#[inline(always)]
@@ -423,12 +457,27 @@ fn add_hl_bc(cpu: &mut Cpu) {
cpu.set_hl(value);
}
+fn ld_hl_u16(cpu: &mut Cpu) {
+ let word = cpu.read_u16();
+ cpu.set_hl(word);
+}
+
fn ld_sp_u16(cpu: &mut Cpu) {
cpu.sp = cpu.read_u16();
}
+fn ld_mhld_a(cpu: &mut Cpu) {
+ cpu.mmu.write(cpu.hl(), cpu.a);
+ cpu.set_hl(cpu.hl().wrapping_sub(1));
+}
+
fn xor_a_a(cpu: &mut Cpu) {
- cpu.a ^= cpu.a
+ cpu.a ^= cpu.a;
+
+ cpu.set_sub(false);
+ cpu.set_zero(cpu.a == 0);
+ cpu.set_half_carry(false);
+ cpu.set_carry(false);
}
fn add_u16_u16(cpu: &mut Cpu, first: u16, second: u16) -> u16 {
diff --git a/src/mmu.rs b/src/mmu.rs
index 6666aeae..a8e95ff0 100644
--- a/src/mmu.rs
+++ b/src/mmu.rs
@@ -20,7 +20,35 @@ impl Mmu {
}
pub fn write(&mut self, addr: u16, value: u8) {
- self.ram[addr as usize] = value;
+ match addr & 0xf000 {
+ // BIOS
+ 0x0000 => {
+ println!("WRITING to BIOS")
+ }
+ // ROM0
+ 0x1000 | 0x2000 | 0x3000 => {
+ println!("WRITING TO ROM 0");
+ }
+ // ROM1 (unbanked) (16k)
+ 0x4000 | 0x5000 | 0x6000 | 0x7000 => {
+ println!("WRITING TO ROM 1");
+ }
+ // Graphics: VRAM (8k)
+ 0x8000 | 0x9000 => {
+ println!("WRITING TO VRAM");
+ self.ppu.vram[(addr & 0x1fff) as usize] = value;
+ }
+ // External RAM (8k)
+ 0xa000 | 0xb000 => {
+ println!("WRITING TO ERAM");
+ }
+ // Working RAM (8k)
+ 0xc000 | 0xd000 => {
+ println!("WRITING TO RAM");
+ self.ram[(addr & 0x1fff) as usize] = value;
+ }
+ _ => panic!("asdad"),
+ }
}
pub fn write_buffer(&mut self, addr: u16, buffer: &[u8]) {
diff --git a/src/ppu.rs b/src/ppu.rs
index 226a07a7..ba7680ed 100644
--- a/src/ppu.rs
+++ b/src/ppu.rs
@@ -1,7 +1,7 @@
pub const VRAM_SIZE: usize = 8192;
pub struct Ppu {
- vram: [u8; VRAM_SIZE],
+ pub vram: [u8; VRAM_SIZE],
}
impl Ppu {
--
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